The word “smog” is a combination of two other words: smoke and fog. Harold Des Voeux, a British physician who was concerned about air quality, is credited with coming up with coining the term in 1911. However, what we refer to as smog has nothing to do with either fog or smoke, usually. Smog is simply another name for air pollution. Scientists refer to it, more precisely, as photochemical smog because it is the result of chemical reactions in the presence of sunlight. The brownish haze associated with smog is the result of nitrogen dioxide in the air, but smog also includes a soup of nitrogen oxides, hydrocarbons, aldehydes, ozone, peroxyethanoyl nitrates (PANs), and suspended particulate matter. Yuck.